Design Study with EV Instrument Clusters

Owned by Taiping Li
Last updated: Jan 08, 2018

Driver Display

Production/Concept Vehicles

With an increasing number of hybrid electric vehicles on the market, auto manufactures are beginning to use LCD based digital displays in place of the traditional dial based instrument clusters. A few examples will be discussed below, both of the traditional approach and the newer digital approach. These will serve as reference for designing MSXII's driver display. 

Chevrolet Volt

  • Battery and Fuel level shown as bars on sides
  • Large numerical speedometer reading 
  • Warning lights on far sides
  • Numerical information on corners 
  • Gear position on top right corner with highlighting




Nissan Leaf

  • Battery and Fuel level shown as bars on sides
  • Separate display for digital speedometer, time, temperature and driving style on the top
  • Gear position with box around for legibility





BMW i3

  • Large digital speedometer in the centre 
  • Battery level and range on the bottom as a bar and numerical readout 
  • Gear position is shown on actual gear lever instead






BMW i8

  • Digital dials and numerical readouts for speed
  • Digital dial for Power % (Similar to tachometer) 
  • Different colours for different driving modes (Eco Pro/Comfort/Sport)
  • Fuel and Battery level depicted as bars on the bottom, with numerical display for range












Audi A3 e-Tron

  • Physical display for speed and % Power
  • Digital bars for battery and fuel level
  • LCD display in the middle for all other information
  • Traditional warning lights



Tesla Model S/X

  • User selectable 'widgets' to display on the sides
  • Speed is represented both by the left hand side of the dial and the large numerical display in the middle
  • Power consumption is shown with the right hand side of the dial, along with an optional  graph
  • Battery level is shown as a green bar in the middle, with a numerical range readout below








Summary

From these vehicles, we can see that multiple automakers adopt similar methods for displaying information to the driver. Although full digital displays are prevailing, lower end vehicles tend to use it in conjunction with either traditional dials, or another display. This seems to be mostly for cost-saving measures, as a single large display both costs more and requires additional computing power to render. Tesla is one of the only manufacture who chooses to display additional information on the instrument cluster, such as energy graphs, navigation, or album art. Traditional manufacture tends to use the infotainment system on the centre console for this instead. 

Some of these similarities are: 

  • Battery/Fuel level is displayed with bars
  • Speed is at least displayed as a numerical number, sometimes supplemented with a digital or physical dial
  • A minimal amount of information is provided when driving normally, so the driver is not overwhelmed 

These similarities should be considered when implementing MSXII's driver display.


With the limited power of a single STM chip used on the controller boards, only a small character based display can be driven. In this case, an instrument cluster similar to the Audi A3 E-Tron should be considered. The LCD will merely used to supplement physical dials and display information such as range, battery voltage, and any additional messages to the driver.  The physical dials can be built or pulled from existing vehicles, but from preliminary research building our own with a stepper motor may be easier to control. 


If a Raspberry Pi Zero is used to drive a LCD panel, then a larger pixel based panel may be used. The BMW i3 or Tesla Model S/X are good starting points for how to display data, as they only display essential information to the driver. Further testing is needed to determine latency and refresh rate before committing to this.